Wireless communication systems have developed through various generations, including a first-generation analog wireless phone service (1G), a second-generation (2G) digital wireless phone service (including interim 2.5G and 2.75G networks) and third-generation (3G) and fourth-generation (4G) high-speed data and Internet-capable wireless services. There are many wireless communication systems in use, including Cellular and Personal Communications Service (PCS) systems. Exemplary cellular systems include the cellular Analog Advanced Mobile Phone System (AMPS), digital cellular systems based on Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), the Global System for Mobile access (GSM) variation of TDMA, and newer hybrid digital communication systems using both TDMA and CDMA technologies. More recently, Long Term Evolution (LTE) has been developed as a wireless communications protocol for mobile phones and other terminals to communicate data at high speeds. LTE is based on GSM, and includes contributions from various GSM-related protocols such as Enhanced Data rates for GSM Evolution (EDGE) and Universal Mobile Telecommunications System (UMTS) protocols such as High-Speed Packet Access (HSPA).
The fifth generation (5G) mobile standard is currently being formulated and calls for higher data transfer speeds, greater numbers of connections, and better coverage, among other improvements. The 5G standard, according to the Next Generation Mobile Networks Alliance, is expected to provide data rates of several tens of megabits per second to each of tens of thousands of users, with one gigabit per second to tens of workers on an office floor. Several hundreds of thousands of simultaneous connections should be supported in order to support large sensor deployments. Consequently, the spectral efficiency of 5G mobile communications should be significantly enhanced compared to the current 4G standard. Furthermore, signaling efficiencies should be enhanced and latency should be substantially reduced compared to current standards.